INTERFACE ROUGHNESS IN FE(100) CR FILM STRUCTURES STUDIED BY CEMS/

Various epitaxial Fe(100)/Cr film structures were MBE-grown on MgO(100 ) and GaAs(100) substrates with the aim to modify the roughness of the Fe/Cr interfaces. By introducing a 2 monolayer thick Fe-57 probe laye r at the interface the distribution of the magnetic hyperfine (hf) fie lds could be measured locally by means of Fe-57 conversion electron Mo ssbauer spectroscopy (GEMS). A simple model is applied which allows th e determination of a pattern of the average interface roughness from t his hf field distribution. It was observed that even samples of high e pitaxial quality according to LEED and RHEED reveal a micro-roughness on a lateral scale of 1-2 nm due to intermixing of Fe and Cr within 1- 2 monolayers.